Phases of augmented hadronic light-front wave functions

It is an important question whether the final/initial state gluonic interactions which lead to naive-time-reversal-odd single-spin asymmetries and diffraction at leading twist cats be associated in a definite way wills the light-front wave function hadronic eigensolutions of QCD. We use light-front time-ordered perturbation theory at the lowest nontrivial order to obtain augmented light-front wave functions which contain an imaginary phase which depends on the choice of advanced or retarded boundary condition for the gauge potential its light-cone gauge. We apply this formalism to the wave functions of the valence Pock states of nucleons and pions, and show how this illuminates the factorization properties of naive-time-reversal-odd transverse momentum dependent observables which arise from rescattering. In particular, one calculates the identical leading-twist Sivers function from the overlap of augmented light-front wave functions that one obtains from explicit calculations of the single-spits asymmetry in semi-inclusive deep inelastic lepton-polarized nucleon scattering where the required phases come from the final-state rescattering of the struck quark with the nucleon spectators. (C) 2010 Elsevier B.V. All rights reserved.